This invention relates generally to pads for computer users to rest their hands on while using accessories such as keyboards, trackballs, and "mice". This invention relates specifically to pads for computer keyboard operators to rest their hands on to reduce stress on the hands, wrists, and arms, most specifically to reduce the risk of developing carpal tunnel syndrome.
Disorders in the upper extremities are frequently seen in people whose jobs require high speed repeated motions. About half of the forty million office workers in the United States alone presently work with video display terminals (VDTs) on the job. As VDT use, both in the numbers of people and the amount of time spent at the VDT, continues to rise in the office place, the number of cases of repetitive stress injury increases apace. Repetitive stress injury is one of the leading occupational health problems of the past decade and shows signs of continued growth in the coming decade.
Repetitive stress injuries resulting from keyboard use can take a number of forms. Steady contraction of the muscles of the upper arms and shoulder-chest region, used to hold the hands and arms outstretched over a keyboard, can lead to muscle fatigue. Muscle fatigue is seldom serious, though, and can be corrected by occasional breaks to rest the arms, and by keeping distances to work materials such as a keyboard to a minimum. Tendons seem susceptible to repetitive stress injury even more so than muscles. Most forms of tendon irritation are either the result of overuse and improper sliding between tendons and other tendons or structures nearby. The resulting inflammation and possible fraying of the tendon can result in the need for extended rest and a change in work habits. Tendonitis, Tenosynovitis, and Epicondylitis are all painful swellings of tendon junctions with muscles, at their point of insertion to the bone, and with their sheaths, respectively. A ganglion is usually a smooth round swelling or inflammation which appears near a joint, such as the wrist, or a tendon sheath; ganglions most often occur on the back of the hand.
More serious tendon injuries include ulnar nerve irritation and carpal tunnel syndrome. Tension on certain flexor muscles in the elbow and wrist can cause compression of the ulnar nerve at the elbow or wrist and result in reduced sensation on the ring and little fingers, as well as loss of dexterity in the hand. Occasionally, such nerve entrapment from repetitive overuse requires surgical release of the nerve. The main nerve of the hand, the median nerve, passes through a narrow tunnel through the wrist formed on the top by the wrist bones and on the bottom by a ligament. The channel, called the "carpal tunnel", also houses the tendons from the forearm muscles responsible for curling or closing the hand and fingers. Blood vessels in the hand also pass through the carpal tunnel. When the hands are bent back or forward sharply there is a three-fold increase in the pressure in the carpal tunnel in comparison to a straight alignment of the hands. The carpal tunnel can be visualized as a straw; when a straw is bent it flattens out and compresses. This increase in carpal tunnel compression may damage the median nerve at this site. Furthermore, the lubrication lining around the tendons may become thick, sticky and swollen due to the wear and tear of repetitive hand movements, thus pressing the nerve against the tunnel. Blood vessels, as well, can be damaged. For some reason, many of the symptoms of repetitive stress injury appear at night or early in the morning and so frequently are not assumed to be related to repetitive motions during the day. A mild case of carpal tunnel syndrome costs $5,000 to $10,000 in medical care and lost work time, according to a study by the American Physical Therapy Association. If not caught in time, surgery often becomes necessary; costs, including surgery to both hands, may rise to $100,000.
From the above it is seen that a device and technique for reducing some of the risk of damage due to frequent computer/keyboard use is desired.